dc

A) (Minimum Band width)/ (Transmission Bit Rate)
B) (Power required)/( Minimum Band width)
C) (Transmission Bit rate)/ (Minimum Band width)
D) (Power Saved during transmission)/(Minimum Band width)
7. The Auto-correlation function of White Noise is [ ]
A) Impulse function B) Constant C) Sampling function D) Step function
8. The minimum band width required for a BPSK signal is equal to [ ]
A) one fourth of bit rate B) twice the bit rate C) half of the bit rate D) bit rate
9. Companding results in [ ]
A)More S/N ratio at higher amplitudes of the base band signal
B) More S/N ratio at lower amplitudes of the base band signal
C) Uniform S/N ratio throughout the base band signal
D) Better S/N ratio at lower frequencies
10. A uniform quantizer is having a step size of .05 volts. This quantizer suffers from a
maximum quantization error of [ ]
A) 0.1V B) 0.025 V C) 0.8 V D) 0.05 V
Cont……2
Code No: 56026 :2: Set No. 4
II Fill in the blanks
11. The Synchronization is defined as _______________________
12. The sampling rate in Delta Modulation is _______________than PCM.
13. The bit error Probability of BPSK system is __________________that of QPSK.
14. Non-coherent detection of FSK signal results in ____________________
15. _____________ is used as a Predictor in a DPCM transmitter.
16. The Nyquist's rate of sampling of an analog signal S(t) for alias free reconstruction is
5000samples/sec. For a signal x(t) = [S(t)]2 ,the corresponding sampling rate in
samples/sec is __________________
17. A Matched filter is used to __________________________
18. A signal extending over -4v to +4v is quantized into 8 levels. The maximum possible
quantization error obtainable is _____________V.
19. The advantage of DPCM over Delta Modulation is _________________________
20. The phases in a QPSK system can be expressed as ______________________
-oOo-
Code No: 56026 Set No. 1
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
III B.Tech. II Sem., II Mid-Term Examinations, April – 2012
DIGITAL COMMUNICATIONS
Objective Exam
Name: ______________________________ Hall Ticket No.
Answer All Questions. All Questions Carry Equal Marks.Time: 20 Min. Marks: 10.
I Choose the correct alternative:
1. Information rate of a source is [ ]
A) maximum when the source is continuous B) the entropy of the source measured in
bits/message
C) a measure of the uncertainty of the communication system
D) the entropy of the source measured in bits/sec.
2. The Hamming Weight of the (6,3) Linear Block coded word 101011 [ ]